nav{
    width: 100%;
    height: 44px;
    text-align: center;
    line-height: 44px;
    background-color: #fff;
}
main{
    position: relative;
    width: 100%;
    background-image: url(../img/advertisement-bg.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: top center;
}
.jump{
    position: absolute;
    top: 28px;
    width: 105px;
    height: 40px;
    right: 14px;
    padding: 7.5px 0;
    line-height: 20px;
    border-radius: 20px 20px 20px 20px;
    text-align: center;
    border: 1px solid rgba(187, 187, 187, 100);
    background-color: #fff;
}
.timer{
    flex: 2;
    height: 25px;
    line-height: 25px;
    text-align: center;
}
.btn{
    flex:3;
    height: 25px;
    line-height: 25px;
    text-align: center;
    border-left: 3px solid #ccc;
}
.text{
    position: absolute;
    bottom: 270px;
    width: 100%;
    font-size: 0;
    opacity: 0;
    color: #fff;
    font-weight: 600;
    text-align: center;
    animation: text 1s forwards;
}
@keyframes text{
    0%{
        bottom: 350px;
        opacity: 0;
        font-size: 0; 
    }
    80%{
        bottom: 80px;
        opacity: 0.8;
        font-size:36px; 
    }
    100%{
        bottom: 100px;
        opacity: 1;
        font-size:48px;   
    }
}